"Ocean Viking", operated by Doctors Without Borders (MSF) and SOS Méditerranée, is stranded off the coast of Libya with around 356 migrants.
The number of migrants stranded in the Mediterranean Sea has risen to more than 500.
Open Arms, the Spanish NGO operating one of the vessels, said they felt "abandoned" and criticised Europe's alleged silence on the matter.
It is now 12 days that the boat has been stranded with around 150 migrants onboard near the Italian island of Lampedusa.
Italy and Malta have refused to take it in.
Another boat, "Ocean Viking", operated by Doctors Without Borders (MSF) and SOS Méditerranée, is stranded off the coast of Libya with around 356 migrants.
Euronews spoke to Sam Turner, head of mission for search and rescue at MSF, who ruled out taking the migrants to Libya.
“Libya is currently an active conflict zone, with fighting still raging in and around Tripoli albeit with a tentative ceasefire in the last few days," he said.
“The situation for migrants as they travel through Libya is one that is clearly, persistently experiencing horrific circumstances be it at the hands of criminal groups such as traffickers where we do hear reports of torture but also in the detention centres themselves, where the conditions are inhumane and the nature of that detention is indiscriminate, indefinite and arbitrary.”
Sam Turner added migrants in Libya had been left with “limited options” to safely travel to the EU or elsewhere to claim asylum.
Watch the full interview with Sam Turner in the video player, above.